Particulate matter exceedences 2006–2013

Source:
Regional councils of Northland, Bay of Plenty, Waikato, Hawke’s Bay, Manawatu-Wanganui, Wellington, Canterbury, West Coast, Otago, Southland; district councils of Marlborough and Tasman; Nelson City Council; Auckland Council

Method:
"This case study assesses the number of airsheds where daily PM10 concentrations exceed the national short-term (daily) standard (National Environmental Standards for Air Quality, 2004) on two or more days. Exceedances occur when daily concentrations are above 50 micrograms per cubic metre (µg/m3). An airshed is a designated area known to have unacceptable levels of pollutants or that may require air-quality management.

This case study uses data from regional council and unitary authority monitoring sites. Monitoring information is only included if the site has
- valid data for 75 percent of the year
- follows good practice approaches (Ministry for the Environment, 2009).

The sample of monitoring sites varies year to year, with additional sites being included if best practice approaches are followed or omitted if not of adequate standard. Generally, those airsheds that do exceed the standard are continually monitored until they regularly no longer exceed the standard.

Some of the monitoring occurs at locations expected to have the highest concentrations (eg close to road traffic or peak urban areas) in that area and may therefore not be representative of the whole population of the area it is located in.


Reference:

Ministry for the Environment (2009). Good practice guide for air quality monitoring and data management. Available from www.mfe.govt.nz."